Different religious denominations teach different criteria for salvation based upon the same Bible teachings that you call obvious. The "truth" must not be that obvious.
There can be only one "truth" in doctrine related to the Elect, losing one's salvation, the requirement of baptism, following God's Law, unforgivable sin, the degree of faith required, etc.
I'm not asking for your opinion on the specific issues listed above, just an acknowledgement that different opinions exist among Christian who are earnestly seeking the truth.
Otherwise, whichever group holds the correct combination of beliefs regarding all issues relating to salvation, is the only group earnestly seeking God, and all others are consciously choosing to remain in sin, but for some reason they pretend to be Christians.